This invention relates to photoelectric smoke detectors and, more particularly, to a detector which senses the presence of smoke with a detection by a light receiving element of scattered light due to smoke particles present in a smoke supervisory zone defined in the detector, the light being projected from a light projecting element to the smoke supervisory zone.
The photoelectric smoke detector of the kind referred to can effectively contribute to highly precise fire alarming such as employed concurrently with a heat detector and the like devices.